INFO: task kworker/u8:5:2907 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:5 state:D stack:21928 pid:2907 tgid:2907 ppid:2 task_flags:0x4248060 flags:0x00004000
Workqueue: writeback wb_workfn (flush-7:9)
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x1798/0x4cc0 kernel/sched/core.c:6961
__schedule_loop kernel/sched/core.c:7043 [inline]
schedule+0x165/0x360 kernel/sched/core.c:7058
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7115
rwsem_down_write_slowpath+0x872/0xfe0 kernel/locking/rwsem.c:1185
__down_write_common kernel/locking/rwsem.c:1317 [inline]
__down_write kernel/locking/rwsem.c:1326 [inline]
down_write+0x1ab/0x1f0 kernel/locking/rwsem.c:1591
ext4_map_blocks+0x765/0x1740 fs/ext4/inode.c:810
mpage_map_one_extent fs/ext4/inode.c:2374 [inline]
mpage_map_and_submit_extent fs/ext4/inode.c:2468 [inline]
ext4_do_writepages+0x1f88/0x4610 fs/ext4/inode.c:2931
ext4_writepages+0x205/0x350 fs/ext4/inode.c:3025
do_writepages+0x32e/0x550 mm/page-writeback.c:2634
__writeback_single_inode+0x145/0xff0 fs/fs-writeback.c:1680
writeback_sb_inodes+0x6c7/0x1010 fs/fs-writeback.c:1976
__writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2047
wb_writeback+0x44f/0xaf0 fs/fs-writeback.c:2158
wb_check_old_data_flush fs/fs-writeback.c:2262 [inline]
wb_do_writeback fs/fs-writeback.c:2315 [inline]
wb_workfn+0xaef/0xef0 fs/fs-writeback.c:2343
process_one_work kernel/workqueue.c:3236 [inline]
process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3319
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x439/0x7d0 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
Showing all locks held in the system:
1 lock held by khungtaskd/31:
#0: ffffffff8e13a0e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e13a0e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
#0: ffffffff8e13a0e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
5 locks held by kworker/u8:5/2907:
#0: ffff88801da9e148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline]
#0: ffff88801da9e148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319
#1: ffffc9000b7d7bc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline]
#1: ffffc9000b7d7bc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319
#2: ffff888027ab40e0 (&type->s_umount_key#32){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:563
#3: ffff888027ab2b98 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: percpu_down_read include/linux/percpu-rwsem.h:77 [inline]
#3: ffff888027ab2b98 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages_down_read fs/ext4/ext4.h:1786 [inline]
#3: ffff888027ab2b98 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages+0x1cc/0x350 fs/ext4/inode.c:3024
#4: ffff88804c9d9590 (&ei->i_data_sem){++++}-{4:4}, at: ext4_map_blocks+0x765/0x1740 fs/ext4/inode.c:810
2 locks held by getty/5620:
#0: ffff888033b200a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc900036bb2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
5 locks held by kworker/u8:12/6800:
#0: ffff88801b2f6948 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline]
#0: ffff88801b2f6948 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319
#1: ffffc9000414fbc0 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline]
#1: ffffc9000414fbc0 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319
#2: ffffffff8f52d090 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf7/0x800 net/core/net_namespace.c:658
#3: ffffffff8f539f48 (rtnl_mutex){+.+.}-{4:4}, at: default_device_exit_batch+0xdc/0x890 net/core/dev.c:12719
#4: ffffffff8e13fb78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:311 [inline]
#4: ffffffff8e13fb78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f6/0x730 kernel/rcu/tree_exp.h:957
4 locks held by syz.9.1837/11700:
#0: ffff888027ab4428 (sb_writers#4){++++}-{0:0}, at: vfs_coredump+0x1daa/0x2a50 fs/coredump.c:1168
#1: ffff88804c9d9700 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline]
#1: ffff88804c9d9700 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: ext4_buffered_write_iter+0x9f/0x3a0 fs/ext4/file.c:294
#2: ffff88804c9d98a0 (mapping.invalidate_lock#2){++++}-{4:4}, at: filemap_invalidate_lock include/linux/fs.h:925 [inline]
#2: ffff88804c9d98a0 (mapping.invalidate_lock#2){++++}-{4:4}, at: ext4_truncate_failed_write fs/ext4/truncate.h:20 [inline]
#2: ffff88804c9d98a0 (mapping.invalidate_lock#2){++++}-{4:4}, at: ext4_write_begin+0x111a/0x19a0 fs/ext4/inode.c:1385
#3: ffff88804c9d9590 (&ei->i_data_sem){++++}-{4:4}, at: ext4_truncate+0x93f/0x1100 fs/ext4/inode.c:4639
3 locks held by kworker/u8:1/13619:
#0: ffff88801a481148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline]
#0: ffff88801a481148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319
#1: ffffc9000b787bc0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline]
#1: ffffc9000b787bc0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319
#2: ffffffff8f539f48 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:303
1 lock held by syz-executor/13990:
#0: ffffffff8f539f48 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#0: ffffffff8f539f48 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
#0: ffffffff8f539f48 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8db/0x1c70 net/core/rtnetlink.c:4056
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
<TASK>
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:328 [inline]
watchdog+0xf93/0xfe0 kernel/hung_task.c:491
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x439/0x7d0 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 2942 Comm: kworker/u8:6 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Workqueue: events_unbound cfg80211_wiphy_work
RIP: 0010:unwind_next_frame+0x395/0x2390 arch/x86/kernel/unwind_orc.c:505
Code: e0 48 c1 e8 03 0f b6 04 28 84 c0 0f 85 6d 19 00 00 4c 89 e8 48 c1 e8 03 0f b6 04 28 84 c0 0f 85 80 19 00 00 41 0f b6 44 24 01 <83> e0 07 0f 84 75 15 00 00 83 f8 01 4c 8b 7c 24 48 48 bd 00 00 00
RSP: 0018:ffffc9000b8b6a78 EFLAGS: 00000246
RAX: 0000000000000002 RBX: ffffffff90206f64 RCX: ffffffff90206f68
RDX: ffffffff90d0e8e4 RSI: ffffffff90d0e8e4 RDI: ffffffff8be33e20
RBP: dffffc0000000000 R08: 0000000000000001 R09: ffffffff8172d195
R10: dffffc0000000000 R11: ffffffff81ac4b00 R12: ffffffff90d0e8e8
R13: ffffffff90d0e8e9 R14: ffffc9000b8b6b48 R15: ffffffff90206f64
FS: 0000000000000000(0000) GS:ffff888125d15000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055557e2dd5c8 CR3: 00000000745a4000 CR4: 0000000000350ef0
Call Trace:
<TASK>
arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
poison_kmalloc_redzone mm/kasan/common.c:388 [inline]
__kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:405
kasan_kmalloc include/linux/kasan.h:260 [inline]
__do_kmalloc_node mm/slub.c:4376 [inline]
__kmalloc_noprof+0x27a/0x4f0 mm/slub.c:4388
kmalloc_noprof include/linux/slab.h:909 [inline]
kzalloc_noprof include/linux/slab.h:1039 [inline]
cfg80211_inform_single_bss_data+0x905/0x1ac0 net/wireless/scan.c:2352
cfg80211_inform_bss_data+0x1fb/0x3b30 net/wireless/scan.c:3235
cfg80211_inform_bss_frame_data+0x3d7/0x730 net/wireless/scan.c:3326
ieee80211_bss_info_update+0x746/0x9e0 net/mac80211/scan.c:226
ieee80211_rx_bss_info net/mac80211/ibss.c:1094 [inline]
ieee80211_rx_mgmt_probe_beacon net/mac80211/ibss.c:1573 [inline]
ieee80211_ibss_rx_queued_mgmt+0xa36/0x2ae0 net/mac80211/ibss.c:1600
ieee80211_iface_process_skb net/mac80211/iface.c:1699 [inline]
ieee80211_iface_work+0x85f/0x12d0 net/mac80211/iface.c:1753
cfg80211_wiphy_work+0x2bb/0x470 net/wireless/core.c:435
process_one_work kernel/workqueue.c:3236 [inline]
process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3319
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x439/0x7d0 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>